The U.S. Supreme Court is debate today whether former President Donald Trump should be removed from Colorado's primary ballot, the first of what could be several legal challenges against Trump to confront the nine justices.

At issue is whether Trump committed "insurrection" by inciting a crowd to storm the U.S. Capitol Jan. 6, 2021, and whether that would make him constitutionally ineligible to be re-elected president. That, in turn, could block him from appearing on a state primary ballot as a candidate for that office.

Oral arguments are underway, and an expedited ruling could come within days or weeks. Spectators began lining up outside the U.S. Supreme Court building on Wednesday with blankets and chairs, hoping to secure one of the few seats reserved for the public.